In recent years, the rapid expansion of the world's population coupled with the accelerated technological development of large sectors of the world has produced a dramatic increase in the demand for energy in all forms including fuels and electricity for heating, lighting, transportation and manufacturing processes. The construction of hydroelectric facilities and the development of fossil fuel resources has continued at a rapid rate, but it becomes increasingly evident for a number of reasons that these efforts are inadequate to keep pace with the demands of the growing population.
Flat plate solar collectors with air and/or fluid flow grooves and tubes have been known with one known flat plate collector being described in the World Book Encyclopedia, (copyrighted 1963 ). This encyclopedia describes the flat plate collector as being made of metal and glass with one or more layers of glass laid over a blackened metal plate. Air spaces are provided between the layers of glass. Air or water passes through tubes under the metal plate to remove the collected thermal energy. The layers of glass in cooperation with the blackened metal plate acts as a heat trap, letting in the sun's rays but keeping most of the heat from escaping again.
A major disadvantage of the known flat plate collectors is that they need auxiliary apparatus to function as a system, i.e., they are not self contained. To be self contained and function as a system, the flat collector must embody an integral liquid storage reservoir embodied in an effective insulated enclosure and it must be kept insulated and isolated from any opportunity to radiate heat to the atmosphere or associated lower temperature bodies.
Even though the known flat plate collectors are efficient in collecting solar energy and are very simple and inexpensive to construct, they have not been developed to their full potential.